In the petroleum refinery industry, production of gasoline by catalytic cracking at higher yield has been highly desired. Since high conversion can be obtained in catalytic cracking using zeolite-type catalysts, there are commonly employed catalysts composed of an inorganic carrier carrying therein zeolite X or zeolite Y, or stabilized zeolite Y such as USY (ultra-stable Y) zeolite to convert light distillates or bottoms (heavy distillate) obtained in an atmospheric distillation or in a vacuum distillation. Such catalysts are well known in the art, and technology related thereto is described, for example, in JP-A-Sho-58-163439 and in U.S. Pat. No. 3,449,070 (the term "JP-A" as used herein signifies "unexamined published Japanese patent application").